JUNE 18 - 22, 2007

THURSDAY, JUNE 21

11:00 am: Science Education Seminar and Open Discussion. Weekly sessions focus on current department programs, literature reviews, and recent trends in science education and assessment. Some sessions feature outside speakers or guests. All members of the CfA community are welcome. Please contact Bruce Ward at bward@cfa, if you wish to attend any session. Phillips Auditorium.

4:00 pm: Summer Colloquium Series. "The Least Luminous Galaxies in the Universe," Beth Willman, CfA. These talks are aimed at undergraduate summer students, but all CfA staff and visitors are welcome. Preceded by refreshments at 3:30 pm. For more information, contact Jonathan McDowell (jcm@cfa, 5-7176). Phillips Auditorium.

Abstract: Since 2005, nearly 20 dwarf galaxies have been discovered around the Milky Way and M31 that are 100 times less luminous than any galaxy previously known. These discoveries are changing our understanding of galaxy formation at the lowest luminosities, and are also currently our most direct tracers of the properties of dark matter on small scales. I will present these discoveries, as well as new follow-up observations that both confirm their residence within dark matter halos and will ultimately reveal their star formation histories. I will then discuss the implications of these results in a cosmological plus galaxy formation context.

FRIDAY, JUNE 22

12:30 pm: Radio and Geoastronomy Division Lunch Talk. "Starless Cores and Deeply Embedded Protostars with Spitzer and Bolocam: A census of the youngest objects in Perseus, Serpens, and Ophiuchus," Dr. Melissa Enoch, California Institute of Technology. Room M-340, 160 Concord Avenue.

Abstract: We have completed an unbiased census of prestellar cores and deeply embedded protostars in Perseus, Serpens, and Ophiuchus, by combining large-scale 1.1 mm surveys and Spitzer c2d maps. I will discuss the properties of the youngest objects in each cloud, and implications for the core formation process, the origin of the stellar initial mass function (IMF), and protostellar evolution. The shape of the combined starless core mass distribution is consistent with recent measurements of the IMF, supporting the idea that stellar masses are directly linked to the core formation process. These dense starless cores have a lifetime similar to that of the entire embedded protostellar phase, 2-5x10^5 yr, or only a few free-fall timescales. Perseus and Serpens contain similar numbers of Class 0 and Class I protostars, suggesting a relatively long Class 0 lifetime of 1-2x10^5 yr, in marked contrast to the very small number of Class 0 sources found in Ophiuchus. Comparing protostellar sources to evolutionary models using the bolometric temperature-luminosity diagram, we find a population of low luminosity Class I sources that are inconsistent with a constant or monotonically decreasing mass accretion rate. This result argues strongly for episodic accretion during the Class I phase, with approximately 25% of sources in a quiescent state.

12:30 pm: Institute for Theory and Computation (ITC) Seminar. "Gamma-Ray Bursts in the Swift Era," Dr. Bing Zhang, University of Nevada, Las Vegas. Pratt Conference Room.

Abstract: The study of gamma-ray bursts has entered a new era since the successful launch of NASA's dedicated GRB mission Swift. I will briefly discuss breakthroughs made in the Swift era, and then focus on some new outstanding problems raised by the Swift observations and the efforts to tackle them. These include the GRB classification schemes, diverse manifestations of the GRB central engine activity, as well as the mysterious temporal breaks in the multi-wavelength afterglows.

SAO HUMAN RESOURCES NOTES

Leave Donations Requested

Due to a medical emergency, Donna Coletti of the Library has been approved as a leave donor recipient in the Leave Transfer Program. Any SAO Trust Fund employee who wishes to donate annual leave to Donna should complete a Leave Donor Form and send it to MS17.

Under the Leave Transfer Program, Trust Fund employees may only donate annual leave to other Trust Fund employees and Federal employees may donate annual leave only to other Federal employees. If you should have any questions or are not able to access the form, please contact Anne LeBlanc, ext. 5-7371.

Job Vacancies

An online listing of all current SAO job openings is available. For more information, please call Human Resources, ext. 5-7371, or view your nearest bulletin board.

A list of scientists currently visiting the CfA is available here.